In a general elevator system, an elevator car and a counterweight are connected to each other by a rope, and the counterweight has a weight that is balanced with the weight of elevator car on which a half of rated number of passengers are onboard. Therefore, when an empty car runs upward, the position energy of counterweight turns a traction machine, so that the traction machine works as a generator, enabling electric power to be regenerated. Inversely, when the empty car runs downward, the traction machine performs power running operation, consuming electric power.
In some conventional elevator control devices, in a plurality of elevator devices connected to a common power supply device, consumed power and regenerative power are monitored, and any car is operated upward or downward so that the total consumed power and the total regenerative power become substantially equal to each other (for example, refer to Patent Literature 1).
Also, in some conventional elevator control devices, elevator cars are divided into a regenerative operation group and a power running operation group, and when the difference in evaluation values of hall calls is within the fixed reference, a hall call is assigned to a car of the regenerative operation group (for example, refer to Patent Literature 2).